U.S. patent number 6,993,239 [Application Number 10/678,526] was granted by the patent office on 2006-01-31 for optical modules employing glass-sealed fiber feedthru with c-seal.
This patent grant is currently assigned to Avanex Corporation. Invention is credited to Giovanni Barbarossa, Ching-Lin Chang, Herbert B. Dela Rosa, William Z. Guan, Khanh T. Ly, Weidong Zhu.
United States Patent |
6,993,239 |
Dela Rosa , et al. |
January 31, 2006 |
Optical modules employing glass-sealed fiber feedthru with
C-seal
Abstract
An optical module box made of aluminum that has a reworkable
glass-sealed fiber feedthru is disclosed. A fiber is inserted
through a glass seal and a C-seal for hermetically sealing an
opening in the optical module box. In a first embodiment, a module
box employing a single-fiber fiber feedthru is described. In a
second embodiment, a module box employing a 2-fiber feedthru is
described. In a third embodiment, a module box employing a ribbon
fiber feedthru is described. A module box having an opening with a
single-fiber feedthru, comprising a C-seal; a glass sealed feedthru
having a front tube and a back tube, the back tube of the glass
sealed feedthru extending through the C-seal; and a fiber passing
through the glass sealed feedthru and the C-seal, thereby
hermetically sealed into the opening of the module box.
Inventors: |
Dela Rosa; Herbert B. (Fremont,
CA), Barbarossa; Giovanni (Saratoga, CA), Guan; William
Z. (Union City, CA), Zhu; Weidong (Fremont, CA), Ly;
Khanh T. (San Jose, CA), Chang; Ching-Lin (Milpitas,
CA) |
Assignee: |
Avanex Corporation (Fremont,
CA)
|
Family
ID: |
34314071 |
Appl.
No.: |
10/678,526 |
Filed: |
October 3, 2003 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050074219 A1 |
Apr 7, 2005 |
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Current U.S.
Class: |
385/138;
385/94 |
Current CPC
Class: |
G02B
6/4428 (20130101); G02B 6/3897 (20130101); G02B
6/4248 (20130101) |
Current International
Class: |
G02B
6/00 (20060101); G02B 6/36 (20060101) |
Field of
Search: |
;385/138,94,88-93 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
EP Search Report, Application No. 04023114.4, dated Jan. 12, 2005.
cited by other.
|
Primary Examiner: Font; Frank G.
Assistant Examiner: Mooney; Michael P.
Attorney, Agent or Firm: Patterson & Sheridan, LLP
Claims
We claim:
1. A module box having an opening with a single-fiber feedthru,
comprising a C-seal; a glass-sealed feedthru having a front tube
and a back tube, the back tube of the glass-sealed feedthru
extending through the C-seal; and a fiber passing through the
glass-sealed feedthru and the C-seal, thereby hermetically sealing
into the opening of the module box made of aluminum.
2. The module box of claim 1, further comprising a feedthru holder
coupled to the front tube of the glass sealed feedthru, the fiber
extending through the feedthru holder, the glass sealed feedthru,
and the C-seal.
3. The module box of claim 2, further comprising a first screw for
pressing a first split lock washer and the feedthru holder into the
module box.
4. The module box of claim 3, further comprising a second screw for
pressing a second split lock washer and the feedthru holder into
the module box.
5. A module box having with a 2-fiber feedthru, comprising: a
C-seal; a glass sealed 2-fiber feedthru with integrated holder
having a fiber retention tubing at a front end and a glass sealing
tubing at a back end, the glass sealing tubing of the glass sealed
2-fiber feedthru with integrated holder extending through the
C-seal; a first fiber passing through the glass sealed 2-fiber
feedthru with integrated holder and the C-seal, thereby
hermetically sealed into a first opening of the module box made of
aluminum; and a second fiber passing through the glass sealed
2-fiber feedthru with integrated holder and the C-seal, thereby
hermetically sealed into a second opening of the module box.
6. The module box of claim 5, further comprising a rubber boot
having a first end and a second end wherein the second end of the
rubber fits into the fiber retention tubing of the glass-sealed
2-fiber feedthru with integrated holder.
7. The module box of claim 6, wherein the glass sealing tubing
fiber of the glass sealed 2-fiber feedthru with integrated holder
has a sufficient length to avoid stress from being imposed on a
glass seal area in the glass sealed 2-fiber feedthru with
integrated holder.
8. The module box of claim 7, further comprising a first screw for
pressing a first split lock washer and the glass sealed 2-fiber
feedthru with integrated holder into the module box.
9. The module box of claim 8, further comprising further comprising
a second screw for pressing a second split lock washer and the
glass sealed 2-fiber feedthru with integrated holder into the
module box.
10. A module box with ribbon fiber feedthru, comprising: a C-seal;
a glass sealed ribbon feedthru with integrated holder having a
fiber retention tubing at a front end and a glass sealing tubing at
a back end, the glass sealing tubing of the glass sealed ribbon
feedthru with integrated holder extending through the C-seal; and a
ribbon fiber passing through the glass sealed ribbon feedthru with
integrated holder and the C-seal, thereby hermetically sealed into
an opening of the module box made of aluminum.
11. The module box of claim 10, further comprising a rubber boot
having a first end and a second end wherein the second end of the
rubber fits into the fiber retention tubing of the glass-sealed
ribbon feedthru with integrated holder.
12. The module box of claim 11, wherein the glass sealing tubing
fiber of the glass sealed ribbon feedthru with integrated holder
has a sufficient length to avoid stress from being imposed on a
glass seal area in the glass sealed ribbon feedthru with integrated
holder.
13. The module box of claim 12, further comprising a first screw
for pressing a first split lock washer and the glass sealed ribbon
feedthru with integrated holder into the module box.
14. The module box of claim 13, further comprising a second screw
for pressing a second split lock washer and the glass sealed ribbon
feedthru with integrated holder into the module box.
Description
BACKGROUND INFORMATION
1. Field of the Invention
The invention relates to the field of telecommunications, and more
particularly to the assembly of optical modules.
2. Description of Related Art
Fiber optics transmission is a common platform for transporting
voice, data, and images. As the demand for data carrying capacity
continues to increase, optical companies are seeking techniques to
utilize the bandwidth of existing fiber-optic cables more
efficiently while enhancing the performance. Typically, the
performance of optical devices is sensitive to its operational
environment, such as humidity and pressure. Optical devices
generally require a tight sealing package, i.e. hermetic sealing
package, in order to prevent moisture or any other gas from passing
through, ensuring a reliable performance during the life span of an
optical module.
Conventionally, sealing techniques using epoxy and aluminum ferrule
have been selected for implementing fiber feedthrus. Both of these
solutions, however, are insufficient in their compliance to a more
stringent sealing requirement. The higher stringent sealing
requirement also makes an optical module more susceptible to
sensitivities. Modernly, optical companies in the telecommunication
industry that make optical modules are required to use a reliable
sealing method which complies with the environmental reliability
specifications in designing and manufacturing optical components
and modules. The epoxy sealing technique is less flexible in that
it is not reworkable. An epoxy-type material fills the pore in
optical fiber holes and the optical package is baked at an elevated
temperature until the epoxy dries. Once the epoxy dries, the
optical module is therefore not reworkable.
Accordingly, it is desirable to have sealing techniques for optical
modules that are less sensitive to meet a more stringent sealing
requirement as well as making the optical module sealing
reworkable.
SUMMARY OF THE INVENTION
The invention describes an optical module box made of aluminum that
employs a glass-sealed fiber feedthru which is reworkable. A fiber
is inserted through a glass seal and a C-seal for hermetically
sealing an opening in the optical module box. In a first
embodiment, a module box employing a single-fiber fiber feedthru is
described. The second embodiment describes a module box that
employs a 2-fiber feedthru. In a third embodiment, a module box
employing a ribbon fiber feedthru is described.
A module box having an opening with a single-fiber feedthru,
comprising a C-seal; a glass-sealed feedthru having a front tube
and a back tube, the back tube of the glass-sealed feedthru
extending through the C-seal; and a fiber passing through the
glass-sealed feedthru and the C-seal, thereby hermetically sealing
into the opening of the module box.
Advantageously, the present invention allows the module box to be
reworkable by using a C-seal, which provides the flexibility for
replacing a fiber connection when necessary.
Other structures and methods are disclosed in the detailed
description below. This summary does not purport to define the
invention. The invention is defined by the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a pictorial diagram illustrating a cross-sectional view
of a module box employing a reworkable glass-seal fiber feedthru
with a C-seal in accordance with the present invention.
FIG. 2 is a pictorial diagram illustrating a first embodiment of a
module box employing a single-fiber feedthru in accordance with the
present invention.
FIG. 3 is a pictorial diagram illustrating a second embodiment of a
module box employing a 2-fiber feedthru in accordance with the
present invention.
FIG. 4 is a pictorial diagram illustrating a third embodiment of a
module box employing a ribbon fiber feedthru in accordance with the
present invention.
FIG. 5 is a pictorial diagram illustrating a sectional view of the
module box employing the 2-fiber feedthru as described with respect
to FIG. 3 in accordance with the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to FIG. 1, there is shown a pictorial diagram
illustrating a module box 100 employing a reworkable glass-seal
fiber feedthru with a C-seal. Three principle elements are used in
hermetically sealing this design: a module box 100 made of
aluminum, a ferrule sub-assembly 110, and a C-seal 120. The ferrule
sub-assembly 110 comprises a glass-seal 130 and a fiber 140. The
ferrule sub-assembly 110 is hermetically sealed by using the glass
seal 130 and the C-seal 120 for sealing the opening where the fiber
140 extends into the module box 100. The fiber 140 extends firstly
through the glass seal 130, extends secondly through the C-seal
120, and subsequently hermetically seals the module box 100. The
ferrule sub-assembly 110 is preferably made of Kovar, or other
similar or equivalent materials.
The C-seal 120 is a metal-to-metal seal that is suitable for
hermetic sealing. The use of the C-seal 120 allows the ferrule
sub-assembly 110 and the fiber 140 to be reworkable when it is
necessary to replace with a new one. A clamp 150 is used to clamp
down a rubber boot 160 for enhancing hermetically sealing of the
fiber 140 into the module box 100. At the entrance of the glass
seal 130 by the fiber 140, an epoxy overfillet 170 is placed in
front of the glass seal 130. The module box 100 can be made of
aluminum or other similar materials that are suitable for hermetic
sealing.
Turning now to FIG. 2, there is shown a pictorial diagram
illustrating a first embodiment of a module box 200 employing a
single-fiber feedthru. In this embodiment, the module box 200 has
two entry openings where a first single-fiber feedthru sub-assembly
210 is hermetically sealed into a first opening of the module box
200 and where a second single-fiber feedthru sub-assembly 250 is
hermetically sealed into a second opening of the module box 200.
One of ordinary skill in the art should recognize that additional
single-fiber feedthrus can be added without departing from the
spirits of the present invention.
A first fiber 220 passes through a first opening in a feedthru
holder 224, a first glass-sealed feedthru 226 and a first C-seal
228 into the first opening of the module box 200. A second fiber
260 passes through a second opening in the feedthru holder 224, a
second glass-sealed feedthru 266, and a second C-seal 268 into the
second opening of the module box 200. The combination of the first
glassed-sealed feedthru 226 pressing through the first C-seal 228
into the first opening of the module box 200 and the second
glassed-sealed feedthru 266 pressing through the second C-seal 268
into the second opening of the module box 200 hermetically seals
the module box 200. A set of screws 223, 243 and 263 are used,
together with a set of split lock washers 222, 242 and 262,
respectively for pressing the feedthru holder 224 into the module
box 200, thereby mechanically sealing the module box 200. The screw
223 passes through a split lock washer 222, passes through a first
opening of the feedthru holder 224, and presses into the module box
200, the screw 243 passes through a split lock washer 242, passes
through a second opening of the feedthru holder 224, and presses
into the module box 200 and the screw 263 passes through a split
lock washer 262, passes through a third opening of the feedthru
holder 224, and presses into the module box 200.
FIG. 3 is a pictorial diagram illustrating a second embodiment of a
module box 300 employing a 2-fiber feedthru. Two fibers, a first
fiber 310 and a second fiber 311, are used with a set of
sub-assembly 305 to hermetically seal the module box 300. The
sub-assembly 305 comprises a first fiber 310, a second fiber 311, a
glass-sealed 2-fiber feedthru with integrated holder 314, and a
C-seal 316, a strain relief or rubber boot 315, a first screw 320,
a first split lock washer 312, a second screw 321 and a second
split lock washer 313. The first fiber 310 passes through a first
opening 314a in the glass-sealed 2-fiber feedthru with integrated
holder 314 and passes through the C-seal 316 into a first opening
of the module box 300. The second fiber 311 passes through a second
opening 314b in the glass-sealed 2-fiber feedthru with integrated
holder 314 and the C-seal 316 into a second opening of the module
box 300. A pair of screws 320 are used, together with a set of
split lock washers 312 and 313, respectively for pressing the
glass-sealed 2-fiber feedthru with integrated holder 314 into the
module box 300, thereby hermetically seals the module box 300. The
screw 320 passes through a split lock washer 312, passes through
the glass-sealed 2-fiber feedthru with integrated holder 314 and
presses into the module box 300. The screw 321 passes through a
split lock washer 313, passes through the glass-sealed 2-fiber
feedthru with integrated holder 314 and presses into the module box
300.
The glass-sealed 2-fiber feedthru with integrated holder 314 has a
fiber retention tubing 314c at a first end and a glass sealing
tubing 314d on a second end. On the first end, the glass-sealed
2-fiber feedthru with integrated holder 314 has the fiber retention
tubing 314c for holding the rubber boot 315 in place. On the second
end, the glass-sealed 2-fiber feedthru with integrated holder 314
has the glass sealing tubing 314d for avoiding stress from imposing
on the glass seal area, such as the area shown in the glass seal
130 in FIG. 1. The glass sealing tubing 314d is preferably designed
with some length so that the sealing area nearing the module box
300 is distant away from the stress area nearing the glass-sealed
2-fiber feedthru with integrated holder 314.
In FIG. 4, there is shown a pictorial diagram illustrating a third
embodiment of a module box 400 employing a ribbon fiber feedthru
sub-assembly 405. The ribbon fiber sub-assembly 405 comprises a
ribbon fiber 410, a glass-sealed ribbon feedthru with integrated
holder 414, a C-seal 416, a strain relief or rubber boot 415, a
first screw 420, a first split lock washer 412, a second screw 421
and a second split lock washer 418. The ribbon fiber 410 passes
through the glass-sealed ribbon feedthru with integrated holder 414
and the C-seal 416 into the module box 400 for hermetic sealing. A
pair of screws 420 and 421 are used, together with a set of split
lock washers 412 and 418, respectively for pressing the glass
sealed ribbon feedthru with integrated holder 414 into the module
box 400, thereby mechanically seals the module box 400. The first
screw 420 passes through the first split lock washer 412, passes
through a first opening 414a in the glass sealed 2-fiber feedthru
with integrated holder 414, and presses into the module box 400,
and the second screw 421 passes through the second split lock
washer 418, passes through a second opening 414b in the glass
sealed 2-fiber feedthru with integrated holder 414, and presses
into the module box 400.
The glass-sealed ribbon feedthru with integrated holder 414 has a
fiber retention tubing 414c at a first end and a glass sealing
tubing 414d on a second end. On the first end, the glass-sealed
ribbon feedthru with integrated holder 414 has the fiber retention
tubing 414c for holding the rubber boot 415 in place. On the second
end, the glass-sealed ribbon feedthru with integrated holder 414
has the glass sealing tubing 414d for avoiding stress from imposing
on the glass seal area, such as the area shown in the glass seal
130 in FIG. 1. The glass sealing tubing 414d is preferably designed
with some length so that the sealing area near the module box 400
is distant away from the stress area near the glass-sealed ribbon
feedthru with integrated holder 414.
FIG. 5 is a pictorial diagram illustrating a cross-sectional view
of the module box 300 employing the 2-fiber feedthru as described
with respect to FIG. 3 that shows the glass seal 130 and the epoxy
fill 170. The glass sealed 2-fiber feedthru with integrated holder
314 holds the first fiber 310 and the second fiber 311 in place,
with the glass seal 130 presses into the module box 300 with the
epoxy fill 170 surrounding the entry into the module box 300 and
the glass seal 130. The C-seal 316 wraps around the glass sealed
2-fiber feedthru with integrated holder 314. The first screw 320
passes through the first split lock washer 312 and presses the
first split lock washer 312 into the module box 300. The second
screw 321 passes through the split lock washer 313 and presses the
second split lock washer 313 into the module box 300. The split
lock washers 312 and 313 are used to maintain the tightness of the
screws 320 and 321, preventing the first and second screws 320 and
321 from becoming loose.
With respect to FIGS. 3 and 5 for the 2-fiber feedthru, during the
assembly of the feedthru with integrated holder 314, areas
surrounding the feedthru 314 and module box 300 that make contacts
with the C-seal 316 are wiped and cleaned using alcohol to remove
any potential oil residual and contaminants on these sealing
surfaces. Screws 320 and 321 are evenly tightened using a torque
wrench to avoid any deformation of the feedthru 314. Similar
practices are applicable to the single-fiber feedthru embodiment as
described with respect to FIG. 2 and the ribbon fiber feedthru
embodiment as described with respect to FIG. 4.
The above embodiments are only illustrative of the principles of
this invention and are not intended to limit the invention to the
particular embodiments described. For example, each of the module
boxes described above can be made of aluminum or other similar
materials that are suitable for hermetic sealing. Moreover, it is
apparent to one of ordinary skill in the art that other types of
glass seal designs may be used without departing from the spirit of
the present invention. Accordingly, various modifications,
adaptations, and combinations of various features of the described
embodiments can be practiced without departing from the scope of
the invention as set forth in the appended claims.
* * * * *